In message <003f01c17cda$353eafe0$0100a8c0@snowdrop>"David Laight" writes
>Is it possible - of course it is :-) everything is possible... - to
>dynamically determine the TCP MSS for a given connection?
It is certainly possible to detect and work around path MTU
discovery black holes. Itojun has a patch to do it for NetBSD.
You're describing here pretty much what it does.
The problem is that we're concerned about the *other* end of
the connection, which needs to implement it as well. It seems
quite a bit tougher to detect this dynamically, and restart
the TCP connection on our end with a smaller TCP MSS.
Proactively making the MSS smaller (without some knowledge
of a problem) sorta ruins the whole point of path MTU discovery.
If you can come up with a way to do it, though, it might
be a win. Good luck!
Kevin
kml@selresearch.net